Much has been written on apologetics of the Old Testament canon and historicity, investigating the Old Testament as an object of apologetics. However, this study is the first comprehensive investigation focusing on apologetics within the Old Testament—i.e., the Old Testament theological foundations of the discipline of Christian apologetics— investigating apologetics as an object of the Old Testament. Taking seriously the biblical texts at its outset, the study presents a biblically based scheme of five types of apologetic strategy: narrative apologetics, prophetic apologetics, wisdom apologetics, “citatory” apologetics as antithetic proclamation, and exemplary apologetics. It focuses on the many explicit confrontations in dialogues, disputes, quotes, and responses, in both prose and poetical form, which are accompanied by an indirect dispute, taking substantial space within the historical parts of the Hebrew Bible. These theological themes are derived from the Old Testament itself, not adapted from the New Testament. This book serves to fill the gap of a proper biblical-theological foundation of the academic field of apologetics. It is a new challenge for all apologists who wish to take seriously the biblical theological foundation of their discipline. With its sole focus on the Hebrew Bible, this study speaks to Jewish scholars as well. It enriches the current discussion on Jewish apologetics, its beginnings and first developments.